Already in Republican Rome adoption came to be used not merely to shore up deficits in family make-up, but also as a means of alliance for elite families – one of a number of strategies which emerged to cement and provide continuity for those families. Only in a relatively small number of cases has anything like enough evidence survived for us to piece together the motives and consequences of such adoptions (Corbier [1991b]). Some scholars have thought that these so-called political adoptions were generically different from those conducted in less significant families, where the custom did no more than provide a childless male with an heir.

Debate also arose amongst jurists during the nineteenth century about apparent differences between imperial adoptions and the theoretical familial situations envisaged in legal sources. The question of whether imperial adoptions were in fact fictitious adoptions arose. Did imperial adoptions simply use existing procedures to achieve unconventional ends? If so the aim might be to provide a kind of proclamation of the succession to the throne. The main result of an imperial adoption was to make the heir apparent a true member of the family. In the third century ad this method of designating a successor was abandoned and letters patent would designate the successor to the throne and give him the title of Caesar. Until that time, it can be seen that the hereditary principle was at least notionally observed.